spring boot backend development course, what is a client

The structure of modern web applications can be broadly divided into clients and servers. The client is responsible for the direct interface with the user, while the server handles business logic and data management. In this course, we will take a closer look at the functions and roles of the client, as well as the interaction with the client in backend development using Spring Boot.

1. Definition of Client

A client refers to a system that provides a user interface. Typically, it is an application like a web browser that sends requests to the server to receive data and displays it to the user. Clients can be divided into several types:

  • Web Client: Provides web pages to the user using HTML, CSS, and JavaScript through a web browser.
  • Mobile Client: Applications running on smartphones or tablets, existing in the form of native apps or hybrid apps.
  • Desktop Client: Desktop applications that run on specific operating systems and can interact with the web.

2. Role of the Client

The main roles of the client are as follows:

  • Providing a user interface: Offers a graphic environment for users to access and manipulate data.
  • Data requests: Sends API requests to the server to fetch necessary data.
  • Response handling: Displays data received from the server on the user’s screen.
  • Validation: Performs validation checks on user input to verify data before sending it to the server.

3. Interaction Between Spring Boot and the Client

Spring Boot helps to easily develop backend applications that can interact with clients through RESTful APIs. RESTful APIs efficiently transmit data between clients and servers via HTTP requests. The client sends requests to the Spring Boot server, and the server responds with data in JSON format.

3.1 Structure of REST API

A REST API fundamentally has the following structure:

  • HTTP Methods: Executes specific actions through methods such as GET, POST, PUT, DELETE.
  • URI: A unique path representing resources, where each API endpoint is mapped to a specific resource.
  • HTTP Status Codes: Numeric codes indicating the result of a request, signaling statuses such as success or failure.

3.2 Implementing REST API in Spring Boot

The process of implementing a REST API using Spring Boot consists of the following steps:

  1. Creating a Spring Boot Project: Use Spring Initializr to generate a project with the necessary dependencies.
  2. Defining Model Classes: Create entity classes that map to the database.
  3. Creating Repository Interfaces: Define JPA repository interfaces for CRUD operations.
  4. Writing Service Classes: Implement business logic in service classes.
  5. Implementing Controllers: Write REST controller classes that handle client requests.

4. Data Processing by the Client

This section explains how clients receive and process data from the server. Clients typically send asynchronous requests to the server using AJAX requests or Fetch API. Once the request is completed, clients process the response data for display to the user.

4.1 Using Fetch API

fetch('https://api.example.com/data')
        .then(response => response.json())
        .then(data => console.log(data))
        .catch(error => console.error('Error:', error));

5. Collaboration Between Client and Server

Collaboration between the client and server is essential to ensure a seamless user experience. The client makes appropriate requests to the server, and the server continuously provides responses to those requests. In this process, API documentation should be easy to understand, and the data format and protocol should be consistent.

6. Future Directions for Clients

The role of the client is expected to become increasingly important in the future. Client-side technologies are continuously evolving to provide interfaces and experiences tailored to various devices and user needs. New frameworks and libraries are emerging, and methods that maximize user experience, such as SPA (Single Page Application), will be core to client technology.

Conclusion

The client plays a very important role in Spring Boot backend development. Through smooth collaboration between the client and server, we can provide the best experience to users. I hope this course helps you understand the relationship between the client and server, and learn the basics of backend development using Spring Boot.